Capacity consoli- dation
Work inspection parking
Annual shutdown
Annual shutdown
Annual shutdown
Annual shutdown
Annual shutdown
Annual shutdown
45
900
Emergency shutdown caused by power loss
40
800
E4101G shutdown for cleaning due to pressure drop increase
700
35
Changed to new SCTC top packings in HDS reactor in 11/2021
HDS reactor (R4101A)
30
600
500
25
Start up of SCTC UMF lter in 10/2020
20
400
Heat exchanger (E4101G)
15
300
10
200
100
5
0
0
Date
Figure 5 Particle size distribution for particles smaller than 6,000 nm (6 µm)
plugging), and both are still operating continuously today. However, this result is not surprising, as the filter perfor - mance has previously been demonstrated under commer- cial operations. 2 Since the previous report² on the same coal tar naph- tha stream, as much as 97.6% solid particles have been removed by the MagAFS filter, and only around 2-3% of the original particles (mostly larger particles) entered the HDS reactor. In fact, smaller particles tend to cause more pressure drop (plugging) problems in the front-end heat exchanger and the HDS reactor. Therefore, in this investigation, the particle size distribu - tion (PSD) analysis of the streams around the MagAFS filter and the HDS reactor is focused on smaller particles using a laser analyser (Horiba LB550) with an upper detection limit of 6,000 nm (6 µm). Samples from the inlet (original coal tar naphtha) and outlet (filtered naphtha feeding the HDS reactor) liquid streams of the filter, and the outlet liquid product stream
of the HDS reactor, were separately shaken with ultra - sonic vibration for a few minutes to break up any lumps or coagulates of the solid particles in the samples. The shaken samples were then settled for 30 minutes to remove larger particles before the PSD of the cleared liquids was ana - lysed. The PSD curves of all samples are plotted in Figure 6 for comparison. As shown in Figure 6, the PSD curve of the filter inlet stream ranges in sizes from 510 to 60,000 nm (almost 72%), while the smaller particles (<510 nm) are masked by the curve due to their tiny quantities. However, the filter is capable of removing most of the larger particles, allow - ing the tiny quantities of small particles in the filter outlet stream to be detected by the analyser, with sizes ranging from 6.6 to 22.5 nm (mostly around 13 nm [0.013 µm]). The analyser also showed particles with sizes from 260 to 1,000 nm (mostly around 400 nm [0.4 µm]) in the filter out - let liquid. The PSD curve of the HDS reactor product ranges from 4.4 to 29.5 nm (mostly around 8 nm [0.008 µm]).
HDS product
After MagAFS lter
Original coal tar feed (before MagAFS lter)
80
71.917
70
60
50
40
30
20
10
0
nm
Figure 6 Solid particle size distribution in original coal tar liquid/in liquid from MagAFS filter/in HDS reactor product
30
Catalysis 2026
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